Question

Mammalian cells are cultured (grown) in a bioreactor. The chemical building blocks of cells are carbon, hydrogen, nitrogen, and oxygen; cells are often modeled as CH_{\alpha }N_{\beta }O\gamma . (A) To begin a batch process, 50L of cells at 100 g/L are initially added to the reactor. After operation, the cells concentration is 25 g/L and the cell mass fills the entire reactor volume of 1000L. Determine the amount of (NH_{4})_{2}SO_{4} to be supplied, assuming that the cells are 12 wt% nitrogen and that (NH_{4})_{2}SO_{4} is the only nitrogen source. (B) During a continuous operation, the steady-state cell concentration in the reactor is 20 g/L, and the cell mass fills the entire reactor volume of 1000 L. Asume that no cells enter the reactor and that the product stream containing the cells leaves the reactor at a rate of 20 L/day. Determine the mass flow rate of (NH_{4})_{2}SO_{4} to be supplied in the feed stream, assuming the cells are 12 wt% nitrogen and that (NH_{4})_{2}SO_{4} is the only nitrogen source. (C) During the batch and continuous operations in the real world, the added nitrogen source is in 20%excess of stoichiometric needs. Redo the calculation for (B), assuming that a 20% excess of nitrogen is supplied in the feed stream.

Answer 1